Hello and welcome to BYC!
Glad you joined.
I also believe Mary is finally defending herself.
As for the blood splatter all over the coop, that will happen with the most innocuous injury. Combs and wattles bleed a lot as they are very vascular. I had a beautiful White Leghorn hen strolling casually around the pen looking as is someone had slit her throat! Her chest was covered in blood. Someone had taken a tiny chunk from the bottom of her wattle. She was oblivious.

I also believe Mary is finally defending herself.
As for the blood splatter all over the coop, that will happen with the most innocuous injury. Combs and wattles bleed a lot as they are very vascular. I had a beautiful White Leghorn hen strolling casually around the pen looking as is someone had slit her throat! Her chest was covered in blood. Someone had taken a tiny chunk from the bottom of her wattle. She was oblivious.